Various techniques for promoting efficiency in the operation of transcribing voice data into text have conventionally been known. For example, known is a technique for estimating and presenting a phrase to be finally inputted while a user is inputting a character string by use of voice data targeted for transcription. As an example, known is a technique for retrieving (searching for) a phrase that at least a part of a character string representing the reading of the phrase agrees with a character string that is being inputted, from among a plurality of phrases obtained by a voice recognition process on voice data, and presenting the retrieved phrase as an input candidate.
However, there is a problem of low accuracy in the conventional techniques since all phrases included in the record of voice recognition process results become search targets; accordingly, the search results in many candidates.